RE: Single finger edge scrolling on Latitude E7240 with Windows 8.1 Pro?
See if you have this file. This executable allows you to enable single finger edge scrolling, but, as I just found out, it goes away and needs to be reapplied after a windows update. Store it somewhere where you will find it next time! 😉
1) Go into c:\program files\DellTPad\
2) In this dir I have
a) DellTouchpad.exe: this is the app called from control panel whose picture you posted.
b) DellTPad.exe alternate utility to set touchpad setting. When launching this I have this option (translating into english) "one finger actions/multi-finger actions", and then it allows you to set single finger vertical/horizontal scrolling.